bitlbee: Always create the ${pidfile} directory and improve rc.d script

- At least on NetBSD every files on /var/run are removed at every
  boot by mountcritlocal rc.d script. Add a bitlbee_precmd() function
  to always check that a directory for the ${pidfile} exists and
  create it if needed.
- Check if /etc/rc.subr exists before source-ing it.
- Introduce BITLBEE_USER and BITLBEE_GROUP variables and reuse them to avoid
  hardcoding `bitlbee' and `nobody' (NFCI)

Index: Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/chat/bitlbee/Makefile,v
retrieving revision 1.75
diff -u -p -r1.75 Makefile
--- Makefile	18 May 2018 17:54:05 -0000	1.75
+++ Makefile	23 May 2018 09:04:46 -0000
@@ -33,18 +33,22 @@ CONF_FILES=		${DATADIR}/motd.txt ${PKG_S
 CONF_FILES+=		${EGDIR}/bitlbee.conf ${PKG_SYSCONFDIR}/bitlbee.conf
 OWN_DIRS+=		${VARBASE}/run/bitlbee
 
-BUILD_DEFS+=		VARBASE
+BUILD_DEFS+=		VARBASE BITLBEE_USER BITLBEE_GROUP
+FILES_SUBST+=		BITLBEE_USER=${BITLBEE_USER} BITLBEE_GROUP=${BITLBEE_GROUP}
 
 EGDIR=			${PREFIX}/share/examples/bitlbee
 DATADIR=		${PREFIX}/share/bitlbee
 DOCDIR=			${PREFIX}/share/doc/bitlbee
 STATEDIR=		${VARBASE}/db/bitlbee
 
-OWN_DIRS_PERMS=		${STATEDIR} bitlbee nobody 700
-OWN_DIRS_PERMS+=	${VARBASE}/run/bitlbee bitlbee nobody 700
+BITLBEE_USER?=		bitlbee
+BITLBEE_GROUP?=		nobody
 
-PKG_GROUPS=		nobody
-PKG_USERS=		bitlbee:nobody
+OWN_DIRS_PERMS=		${STATEDIR} ${BITLBEE_USER} ${BITLBEE_GROUP} 700
+OWN_DIRS_PERMS+=	${VARBASE}/run/bitlbee ${BITLBEE_USER} ${BITLBEE_GROUP} 700
+
+PKG_GROUPS=		${BITLBEE_GROUP}
+PKG_USERS=		${BITLBEE_USER}:${BITLBEE_GROUP}
 PKG_HOME.bitlbee=	${VARBASE}/db/bitlbee
 
 INSTALLATION_DIRS=	${PKGMANDIR}/man5 ${PKGMANDIR}/man8 sbin
Index: files/bitlbee.sh
===================================================================
RCS file: /cvsroot/pkgsrc/chat/bitlbee/files/bitlbee.sh,v
retrieving revision 1.3
diff -u -p -r1.3 bitlbee.sh
--- files/bitlbee.sh	7 Oct 2011 22:37:03 -0000	1.3
+++ files/bitlbee.sh	23 May 2018 09:04:46 -0000
@@ -3,13 +3,25 @@
 # PROVIDE: bitlbee
 # REQUIRE: DAEMON
 
-. /etc/rc.subr
+if [ -f /etc/rc.subr ]; then
+	. /etc/rc.subr
+fi
 
 name="bitlbee"
 rcvar=$name
 command="@PREFIX@/sbin/bitlbee"
 pidfile="@VARBASE@/run/${name}/pid"
 command_args="-D"	# run as a daemon
+start_precmd="bitlbee_precmd"
+
+bitlbee_precmd()
+{
+	if [ ! -d "@VARBASE@/run/${name}" ]; then
+		@MKDIR@ "@VARBASE@/run/${name}"
+		@CHMOD@ 0700 "@VARBASE@/run/${name}"
+		@CHOWN@ @BITLBEE_USER@:@BITLBEE_GROUP@ "@VARBASE@/run/${name}"
+	fi
+}
 
 if [ -f /etc/rc.subr ]; then
 	load_rc_config $name